Red cotton dye and process of making same.



amino s'ra'rns PATENT orrion.

RUDOLF SOHIILE, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR TO OASSELLA COLOR COMPANY, OF NEW YORK, N. Y.

REID COTTON DYE AND PROCESS OF MAKING SAME.

To all whom it may concern:

Be it known that I, RUnoLr SoHt'iLn, doctor of philosophy, a Swiss subject, and a resident o'l' Franktort-on-the-lvlain, VValdschmidtstrasse 26, have invented certain new and useful Improvements in the Manufacture of Red Cotton Dyestuiis, of which the following is a specification.

I have discovered that by combining one molecule of diazotized m-aminophenyl-5- oxy-1.2-naphtimidazole-7-sulfonic acid or its dihydro derivative (hereinafter called imidazole acids) with a second molecule of imidazole acid, very valuable polyazo dyestuffs may be obtained containing a group, such as hereinafter called a "double imidazole body. This group may be formed by combining the molecules in an alkaline solution and may then be combined with one molecule of a diazo compound for instance paradiazo benzene-suli'onic acid. An easily soluble dyestuff of excellent afiinity is thereby produced, whereas the dyestuil from paradiazobenzenesul'l'onic acid and one molecule of imidazole acid hardly stains cotton. Dyestuffs containing the double group may also be obtained by diazotizing the monoazo dyestuffs obtained from the imidazole acids, and then combining with a second molecule of imidazole acid. Now, if these disazo dyestuffs are diazotized and developed on the fiber, dyeings fast to washing are obtained which are also distinguished by their great resistance to acids. IJith regard to the shades of the trisazo dyestuffs so obtained on the fiber, it is remarkable that the introduction of the second molecule of the imidazole acid does not affect the brilliancy. The dyestuffs yield yellowish-red to bluishred shades, brighter if anything than the analogous products containing but one molecule of the imidazole acid. Their tinctorial Specification of Letters Patent.

Application filed November 16, 1908.

Patented Feb. 9, 1909.

Serial No. 462,902.

power on the other hand is considerably enanced in consequence of the increased number of the azo groups.

The process is illustrated by the following example:

Example :19.9 kilos of the sodium salt of sulfanilic acid are diazotized with 36 kilos hydrochloric acid of 21 Be. and 7 kilos sodium nitrite. The diazo compound is introduced into a solution, brought to 0 C. by the addition of ice, of 38 kilos m-aminophenyl-5- oXy-1.2-dihydronaphthimid-azole 7 sulfonic acid, dissolved with 40 kilos anhydrous carbonate of soda. After two hours it is heated to 70 O. the dyestuil salted out and filtered off. For further diazotation, the dyestufi is stirred to a aste with water. The suspension is coolec With ice to 0 O., and 48 kilos hydrochloric acid of 21 Be. and 7 kilos sodium nitrite are added. The diazo compound is formed after about 5 to 6 hours. It is introduced into a solution of 38 kilos m-aminophenyl-5-oX -1.2 dihydronaphtimida zole 7-sulfonic acid and 40 kilos anhydrous carbonate of soda. After heating a short time the coloring matter is salted out. The dyestufl is filtered oil and dried. It forms a brown powder, dissolving in water with a brilliant red color. In concentrated sulfuric acid it dissolves with a bluish-red color. It dyes cotton scarlet shades, and such dyeings when developed with beta naphthol yield scarlet red shades. If in this example for the sulfanilic acid there be substituted o-toluidinp-sulfonic acid, o-anisidin-psulfonic acid or betanaphtylamin-sulfonic acids, dyestuffs of a more bluish shade are obtained, which when developed with beta naphthol, yield in a like manner considerably more bluish shades than are obtained with the sulfanilic acid dyestuffs under the same conditions.

Having now particularly described and as certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. The manufacture of azo compounds by combining one molecule of diazotized imidazolacid with a second molecule of imidazol acid substantially as described.

2. The manufacture of azo compounds by diazotizing a monoazo compound of an imidazol acid and combining with a second molecule of imidazol acid substantially as described.

a van, 1026 3. The manufacture of dyestufis by reactscarlet shades and such dyeings, when deing with a diazo compound on a double imiveloped with beta naphthol, yielding scarlet dazol body substantially as described. red shades substantially as described.

4. The new dyestufi of the constitution In witness whereof I have hereunto signed 5 R N=\I imidaZO1aOid N= filly name thisf26th day 0? Qctober 1908, in 15 imidazolacid e p1 esence 0 two subsciibmg witnesses. RUDOLF SCHULE. which is a brown powder dissolving in water Witnesses: with a red color, in concentrated sulfuric JEAN GRUND,

0 acid with a bluish-red color, dyeing cotton CARL GRUND. 

